Terahertz time-domain spectroscopy (THz-TDS) relies heavily on knowing precisely the thickness or refractive index of a material. In practice, one of these values is assumed to be known, or their product is numerically optimized to converge on suitable values. Both approaches are prone to errors and may mask some real features or properties of the material being studied. To eliminate these errors, we use THz-TDS in reflection geometry to accurately and independently determine both thickness and refractive index by illuminating the step-edge of a substrate atop a metal stage. This method relies solely on the relative time delay among three reflected pulses, and therefore forgoes the need for optimization or assumption of substrate parameters.
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http://dx.doi.org/10.1364/OE.26.001697 | DOI Listing |
BMC Ophthalmol
January 2025
Department of Refractive Surgery, Guangzhou Aier Eye Hospital, Jinan University, Guangzhou City, Guangdong Province, 510000, China.
Purpose: To evaluate the impact of Implantable Collamer Lens (ICL) implantation on anterior chamber angle parameters and posterior segment structures in highly myopic eyes and explore potential correlations between these changes. The study aimed to assess alterations in superficial and deep vessel density (SVD, DVD), foveal avascular zone (FAZ) area, and retinal nerve fiber layer (RNFL) thickness to clarify the safety profile of ICL implantation.
Methods: Prospective observational study, included 36 highly myopic eyes undergoing ICL implantation in surgery group and 23 non-surgical control eyes in non-surgery group.
Sci Rep
January 2025
Aswan Regional Earthquake Research Center, National Research Institute of Astronomy and Geophysics (NRIAG), Helwan, Egypt.
The seismic refraction technique has demonstrated its efficiency as a cost-effective geophysical approach for bedrock investigation, which is very important for major construction projects. In the southern part of New Qena City, in the Eastern Desert of Egypt, construction of many domestic facilities is planned. Therefore, a prior investigation focusing on bedrock is required to validate the site for construction and other projects.
View Article and Find Full Text PDFBMC Ophthalmol
January 2025
Department of Ophthalmology, The First Affiliated Hospital of Bengbu Medical University, Bengbu, Anhui, 233004, China.
Objectives: To evaluate the effects of short-acting cycloplegic agents, tropicamide and compound tropicamide, on ocular biological parameters and choroid thickness.
Methods: In this study, seventy pediatric subjects aged 6 to 13 years were randomly assigned to two groups: the tropicamide group and compound tropicamide group. Ocular biological parameters and choroidal thickness (CT) and subfoveal choroid thickness (SFCT) were measured in both groups and were retested 40 min after drug administration.
Front Med (Lausanne)
January 2025
Chongqing Key Laboratory of Ophthalmology, Chongqing Eye Institute, Chongqing Branch (Municipality Division) of National Clinical Research Center for Ocular Diseases, Department of Ophthalmology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China.
Objective: To investigate and evaluate the progression of myopia and associated factors of axial length (AL) growth among children in Chongqing.
Methods: This six-month prospective study was conducted on students in grades 1 to 8 at a school in Chongqing, China. All participants underwent a standard ophthalmologic examination including uncorrected visual acuity (UCVA), noncycloplegic refraction, AL, and corneal topography in March 2023.
Int Med Case Rep J
January 2025
Department of Ophthalmology, University of California San Francisco, San Francisco, CA, USA.
Purpose: To compare the outcomes of two different surgical planning strategies for topography-guided repair of post-LASIK ectasia.
Methods: This is a case report of a patient presenting with post-LASIK ectasia. A retrospective chart review was used to collect details of the ophthalmic exam, as well as ocular imaging such as anterior segment optical coherence tomography and Scheimpflug corneal tomography.
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